Mariah Carey's brother says she abandoned family

Mariah Carey has been called out by her own brother, who is accusing the singer of abandoning her troubled sister following her prostitution arrest.

Speaking to Inside Edition from Florence, Italy, Mariah's older brother, Morgan, 51, spoke about his broken family, saying: "Mariah doesn't care about anyone other than herself."

Read: JonBenet Ramsey's Brother Decided to Speak Out to Honor Sister's Memory, He Tells Dr. Phil

Alison Carey, 55, was arrested on prostitution charges earlier week at a low budget motel in upstate New York. She has pleaded not guilty.

Cops say she placed an online ad soliciting sex that borrowed lines from her sister's 1996 hit, "Fantasy."

See photos of Mariah Carey through the years:

"I'm a pretty lady looking for guys...with me it's such a sweet, sweet fantasy baby!" the ad read.

The arrest is the latest crisis for Alison, who in her younger days wanted to be a singer just like Mariah, but she ended up battling drugs and falling on hard times.

Morgan said: "I would hope Mariah could find it in her heart to forgive Alison her transgressions and step up, create a trust, let's make sure Alison's needs are met."

Morgan and Mariah were once very close. In fact, Morgan — a model and music producer — claims he was instrumental in Mariah becoming a superstar.

"There wouldn't be a Mariah Carey today if it hadn't been for me," he claims.

He says he has not spoken to Mariah in six years following a nasty rift tore them apart.

Morgan says he's upset because Mariah refuses to help Alison, even after she recorded a desperate public plea for help in March.

Read: Mariah Carey's Ailing Sister Begs For Her Help: 'Please Don't Abandon Me'

Mariah's publicist says she has done a lot over the years to give Alison a helping hand.

"Through the years, Mariah has spent hundreds of thousands of dollars supporting Alison and her children," the statement said.

Morgan says: "I will always be puzzled why Alison, a heroin addict, has always been given large sums of money from Mariah her whole life. You can't put large sums of cash into the hands of a drug addict."

Incredibly, Morgan fears retaliation from his famous sister and her fans for speaking out.

"It's about protecting this fiction she has created, this image she has created, it's about keeping the darkest secrets covered up," he said.

It is believed Mariah has not spoken to her sister since 1994.

Watch: Why Mariah Carey's 'All I Want For Christmas Is You' Was Almost Never Recorded